Patients with disseminated malignancies for which no curative therapy exists or who have failed standard therapy have been entered into a Phase I Trial of human leukocyte interferon prepared by recombinant DNA technology and supplied to the NCI by Hoffmann-La Roche. This trial is designed to determine the maximum tolerated and optimal immunomodulatory doses of this interferon preparation in cancer patients, as well as to study its pharmacokinetics and antitumor effect. Requirements for entry include good performance status and normal hematologic, hepatic, and renal function as judged by routine clinical tests. Different patients receive increasing doses (one dose/five patients) of interferon by intramuscular injection for 28 days on a twice daily schedule (BRMP Protocol #81-01/Roche Protocol #2328) or three times weekly schedule (BRMP Protocol #8102/Roche Protocol #2329). To date approximately 20 patients have been entered on each of the two treatment schedules. Objective antitumor responses have been seen in a limited number of patients. Toxicities observed include fever, fatigue, anorexia and neutropenia. The study continues.